Dumbbells are often used in muscle-building or muscle-toning exercises. However, a traditional dumbbell, i.e., a pair of weights connected by a short bar serving as a handle, is not appropriate for all exercises and alternative forms of weights have been developed for different exercises.
One weighted exercise device that was considered to be particularly useful for gymnastic exercises is disclosed in U.S. Pat. No. 113,966 (Ballou) and comprises a spherical or spheroidal lower part that is elongated or extended on one side. The weighted exercise device includes a hollow cavity and includes an opening in the elongated or extended part leading into the cavity. A handle extends across the cavity and is positioned to enable a user to extend their hand into the cavity and grasp the handle. The only manner in which this weighted exercise device may be used is by gripping the handle
Other weighted exercise devices include those disclosed in U.S. Pat. Nos. 4,813,669; 4,880,228; and 4,900,016 (all to Caruthers).
Another exercise device is a Bosu® balance trainer that has a rim that can be gripped. This balance trainer is constructed of rubber and plastic and is not weighted.